I have the typical issue with the Gen 3 cylinder misfire, losing coolant. As a stop gap before I get a rebuilt engine dropped in, I’m looking for recommendations on what additive to use to attempt to seal the head gasket leak?
I would avoid that crap, there's a good chance it'll clog your radiator, cabin heater core and so on. And get right on the head gasket replacement, before it turns into a bent piston arm. How many miles on it? Has the EGR been cleaned?
I would avoid that stuff like the plague. But since you are dropping in a replacement engine anyway, you may be able to get away with using K-Seal if you bypass the heater core circuit. Just plan on also replacing the radiator when you complete the engine swap. Any other component would be replaced with the engine swap anyway.
I’d just keep adding coolant. The head gasket will eventually fail anyway, even with sealer added. The sealer will only cause added expense later on. Heater core, thermostat, radiator, etc.
Thank you The coolant is getting mixed with the oil so that’s got to be bad for the cylinders/pistons?
With 116K miles the EGR system is likely partially clogged, and what gas that is flowing through is not being cooled enough, again due to the carbon buildup. There's a rectangular passage with a coolant supplied radiator that the air flows. When new it's clean, free-flowing, and the radiator fins cool the exhaust air passing through. Over time it clogs with carbon, and the carbon insulates the fins, prevents them from cooling as effectively. All this leads to an engine running hotter. The PCV circuit also, is steadily dumping an oil/water/gas mist into the intake manifold. At this point, it's likely best to focus on fixing the head gasket first.
116,000 still seems like low mileage even with the EGR. What is the lowest miles people have seen with the blown head gasket for the Gen III?
If you are the DIY type, there is a video on YouTube of a pair of guys doing a Prius head gasket. Their video is 30 minutes or so long, but it is less then an 8 hour job start to finish. About $116 for Toyota head bolts I paid 11.60 per bolt) and 35 for aftermarket head gasket or 150 for the Toyota valve grind gasket set if I recall. 80 for antifreeze and oil. I bought Peak brand Toyota Pink antifreeze for 16 a gallon, then about 40 for the full syn Mobil 1 and filter.
2011 Prius Head Gasket Failure | Page 5 | PriusChat 2011 Prius Head Gasket Failure | Page 5 | PriusChat
Those ain't leaves in the water. This is just from the heat exchange recovery. Heater core came out cloudy with bubbles but no particles. I kept swapping water flow with low PSI. I was reading the repair manual someone had posted. It states to fill the recovery tank with coolant. I always filled from reservoir. I'll fill coolant into exhaust recovery tank and heater core. Then seal everything up and start from the reservoir.
I replaced radiator thinking that was causing my overheating issue. But that wasn't it. I did see some residue on one side of the radiator, near the small opening for the reservoir. I've flushed the heater core, hardly any debris came out. Heater does work. Lines coming from firewall are all hot. Only my lower radiator hose coming from the water pump stays cool. I plan on dropping the exhaust and inspecting the exhaust recovery. So far i've flushed out EGR cooler, throttle body, heater core, heat exchange, reservoir, and the radiator. The coolant reservoir was by far the dirtiest followed by the radiator. One day i'll cut my old radiator open just to see how it looks on the inside.
I've tried three thermostats, two water pumps. Two oem and 1 Gates brand. This was my original thermostat with 188k old motor with blown head gasket. I just removed it prior to engine swap. I pulled it off to inspect it and the water pump. You can see all the residue from the K seal. I plan on drilling a hole through the center of thermostat but that would trigger a check engine light from what i'm told. Though I haven't seen one on a prius related to a thermostat. I've seen other cars with DTCs related to the thermostat being stuck open.
Going to boil the mix and pump into exhaust recovery tank see if any more garbage comes out. That way with the heat I can see if the actuator pushes out. I took a few pictures of the pieces I took off. I'll try to take one from underneath the car. There was a chunk of some debris when I first removed the cover. Second picture you can still some of it. The other end theres a spring that controls the door for exhaust back flow. That was moving freely I can move the spring easy by hand.
@NutzAboutBolts video links are pinned at top of 3rd gen Maintenance Forum. Also, a couple of good threads: EGR & Intake Manifold Clean Results | PriusChat Oil Catch Can, Eliminate that knock! | PriusChat And some Repair Manual info, mainly torque values:
